Mitutoyo 188-101 Whitworth (BSW) Screw Pitch Gauge 4-42 TPI

Thread pitch size is stamped on each gauge.
Composition of leaves Unified: 4, 4.1/2, 5, 5.1/2, 6, 7, 8, 9, 10, 11, 11.1/2, 12, 13 14, 15, 16, 18, 20, 22, 24, 26, 27, 28, 30, 32, 34, 36, 38, 40, 42 TPI. (30 leaves).